Quote:
Originally Posted by kornelski
I'd like to add support for YCoCg color space in my AVIF image compressor. I can easily find RGB to YCoCg formulas (including the original YCoCg paper) that are equivalent of a matrix rotation, but I'm missing a second formula that scales the result to actual bytes to be encoded.
All the sources I can find assume it's lossless and/or Co/Cg can be negative, but that means a conversion of 8-bit RGB to YCoCg gives 9- or 10-bit values. How am I supposed to store that in 8-bit unsigned bytes of YUV channels when encoding? |
U and V are also signed, with "0" meaning no chroma for that channel and saturation coming from absolute value. It's really only luma or native RGB that are purely unsigned. You should be able to treat other chroma formats identically, and the codec itself doesn't really care.